This invention relates to methods and apparatus for predicting breakdowns of vehicles, such as locomotives.
A locomotive is a complex electromechanical vehicle comprised of several complex systems. Each of these systems is built from components which over time may fail. When a component does fail, it is difficult to identify the failed component because the effects or problems that the failure has on the system are often neither obvious in terms of their source nor unique. The ability to automatically diagnose problems that have occurred or will occur in the locomotive systems has a positive impact on minimizing locomotive downtime.
Previous attempts to diagnose problems occurring in a locomotive have been performed by experienced personnel who have in-depth individual training and experience in working with locomotives. Typically, these experienced individuals use available information that has been recorded in a log. Looking through the log, the experienced individuals use their accumulated experience and training in mapping incidents occurring in locomotive systems to problems that may be causing the incidents. If the incident-problem scenario is simple, then this approach works fairly well. However, if the incident-problem scenario is complex, then it is very difficult to diagnose and correct any failures associated with the incidents.
Currently, computer-based systems are being used to automatically diagnose problems in a locomotive in order to overcome some of the disadvantages associated with relying completely on experienced personnel. Typically, a computer-based system utilizes a mapping between the observed symptoms of the failures and the equipment problems using techniques such as table look ups, a symptom-problem matrices, and production rules. These techniques work well for simplified systems having simple mappings between symptoms and problems. However, complex equipment and process diagnostics seldom have such simple correspondences. In addition, not all symptoms are necessarily present if a problem has occurred, thus making other approaches more cumbersome.
The above-mentioned approaches either take a considerable amount of time before failures are diagnosed, or provide less than reliable results, or are unable to work well in complex systems. There is a need to be able to quickly and efficiently determine the cause of any failures occurring in the locomotive systems, while minimizing the need for human intervention.
U.S. Pat. No. 5,845,272 discloses an on-board locomotive diagnostic system. The system is useful for identifying locomotive systems problems and proposing remedial measures to repair or correct the problems. On-board diagnostic systems, however, do not presently communicate with a rail carrier's maintenance or scheduling centers. Consequently, those centers do not have direct access to systems data from remote locomotives which would be helpful in optimizing locomotive maintenance scheduling and route planning while minimizing locomotive downtime arising from unexpected breakdowns.
Accordingly, it is especially desirable to avoid faults resulting in unscheduled shutting down or slowing down vehicle operation, since such shutdowns or slowdowns are costly and highly inconvenient.
It is also desirable to provide a way of predicting faults and dealing with predicted faults before they occur.